1. Field of the Invention
The invention is to a heat exchanger wherein the porosity and hydrophilic/oleophilic characteristics of the plate or wall between air streams and along air streams is controlled to selectively control recirculation, heat and moisture transfer, and filtration between the air streams.
2. Description of Related Art
The conservation of energy during the ventilation and air conditioning of commercial, residential and industrial buildings is a standard procedure. It is common to transfer both heat and moisture, i.e. enthalpy transfer of both sensible and latent energy. The water vapor in air is transferred from the more humid air to the less humid air. This means that usually moisture transfer will be from warm inside air to cold outside air, during winter, and from the outside warm air to the cool inside air, during summer.
The use of various heat exchange systems and variations of each basic type are old with counter flow, cross flow, and parallel flow being the most used basic types with combinations of them also in use. The counter flow type is generally considered to be the most efficient. The spacing between the heat exchange surfaces has been controlled by various means including spacers, end securing, Sweed et al, U.S. Pat. No. 4,101,287, issued 18 Jul. 1978; side securing, Real et al, U.S. Pat. No. 4,501,321, issued 26 Feb. 1985; surface deformations, Thunberg, U.S. Pat. No. 4,391,321, issued 5 Jul. 1983, and, particles, Saito et al, U.S. Pat. No. 4,911,227, issued 27 Mar. 1990.
The transfer of both heat and moisture across heat exchange surfaces or plates is disclosed by H. Harrison in U.S. Pat. No. 4,040,804, issued 9 Aug. 1977, who uses a water permeable or deliquescent paper. Okamoto et al in U.S. Pat. No. 4,377,400, issued 22 Mar. 1983, use a paper-like material of carbon fibers and binding fibers for heat exchange and moisture transfer by diffusion of vapor molecules and capillary action. Yano et al, U.S. Pat. No. 4,582,129, issued 15 Apr. 1986, teach alternative heat transfer element structures including hygroscopic moisture transmission.
Meyer et al, U.S. Pat. No. 4,172,164, issued 23 Oct. 1979, use a hydrophilic coating or layer on an impermeable backing for moisture transfer in a rotary heat exchanger and V. Kubicek, U.S. Pat. No. 4,157,929, issued 12 Jun. 1979, teaches that a porous glass fiber structure coated with a ceramic can alternately be used in the heat exchange process.